STOCKTON - The mother of missing 23-year-old Dalene Carlson wrote an open letter Wednesday begging for answers to her daughter's disappearance going on three weeks now.

Narlene Flagg of Sandpoint, Idaho, in her one-page hand-written letter, pleads with any witnesses of the apparent crime to step forward. She also addresses the unknown person responsible for causing her daughter to vanish mysteriously.

"Why?? Please, please whoever knows or seen anything - please let us know - she doesn't deserve this selfish act," Flagg wrote, describing her daughter as a trusting person who cared about the people she met.

"WHAT HAS SHE DONE TO YOU?" Flagg wrote.

The case launched by family-crimes investigators has now been turned over to homicide detectives, and a search taking several days along the Calaveras River near University of the Pacific has ended, Stockton police spokesman Officer Pete Smith said.

Smith said that a flip-flop found during the river search has been sent off for forensic analysis. It has yet to be confirmed if the shoe belonged to Carlson.

Carlson, who recently moved to Stockton from Idaho, was last seen by friends Aug. 7 at Finnegan's Pub and Grill on Pacific Avenue. A Food 4 Less surveillance camera then captured her making a purchase with friend Jason Gilley.

Police initially arrested Gilley, 25, but no charges were filed and he was released. Yet Gilley and two other acquaintances of Carlson - Jacob Evangelisti and James Cosens - remain persons of interest in the case, Smith said.

Margret Baker, the aunt with whom Carlson lived in Stockton, said she met Evangelisti once. He and Carlson dated, but Baker said her niece never considered him a boyfriend.

Baker said her sister - Carlson's mother - has been staying with her in Stockton amid the search, but she was too distraught to speak publicly. Baker provided The Record with Flagg's letter in an effort to keep the story in the public's eye.

Supporters have set up a Facebook page called, "Dalene Carlson - Missing from Stockton, California since August 7, 2011." By Wednesday, it had gathered 1,633 followers. It includes pictures and a missing-person flier.

The Facebook page also includes the latest news stories on Carlson and comments from well-wishers.

"So devastating," one visitor wrote. "My eyes are always on alert looking for her here in Stockton. Prayers to the family and friends."

Baker said police have told her and Flagg that detectives have new leads, but they won't share specifics with them. Baker said it feels like her niece walked off the end of the Earth.

For her part, Flagg says in the letter that she is "distraught and so very angry." Her only wish is to have her daughter home. Flagg ends the letter speaking directly to her daughter.

"Sissy, if there is a way for you to come home please call - we are here for you - I love you Sis - I want to hear your voice!"